Process for manufacturing a cellulose ester molding batch having a metallic appearance and the batch produced thereby



Patented Aug. 20, 1946 r PROCESS FOR MANUFACTURING A CELLU- LOSE ESTERMOLDING BATCH HAVING .A METALLIC APPEARANCE AND THE BATCH PRODUCEDTHEREBY ihomas J. Hillery, Boonton, N. J., assignor to George Benda,tion of New Jersey Inc., Boonton, N. 5., a corpora- N Drawing.Application October 2, 1943, Serial No. 504,782

Claims. 1

This invention relates to a proces for manufacturing a batch of moldedmaterial which gives a metallic appearance as of brass, bronze, silver,chrome or gold. The invention also applies to plastic molding materialprocessed so that any ob; ject molded of the material gives thappearance of being made of one of said metals.

The plastic compound used for this process may be identified by its urearesin base or cellulose acetate base. Materials of the urea resin base,

in place of the bronze flake in such as formaldehyde urea resin, ispreferable in the natural shade and may include an of the varied fillersused in moldin compounds, prepared with this base.

The basic molding substance used is ground to a fineness of sandparticles, which has a fineness suitable for introduction into astamping machine. The stamping machine used consists preferably of arevolving-cam, for lifting and dropping a shaft to which are attachedsteel shoes that strike against the bottom of a kettle of steel. Thisprocess produces a flaked or floured material.

The thus obtained basic molding material is introduced in this stampinmachine together with a small quantity of binding grease such as lard,for instance, to give to said material body a flour like or flakyconsistency. The time required for reducing the molding material from agrain to a floured or flaked consistency depends upon the type ofmaterial used.

The stamping process, no matter what basic material is used, iscontinued until the same is reduced to a floured or flaked consistencyof about 200 mesh,

In order to produce a batch of molding material, which simulates brass,bronze, gold, silver or chrome, it is now necessary to add to thisflaked basic material a quantity of bronze in flakes of about 200 meshin the case of alloys of brass, bronze and gold or aluminum ink flake,and also in case or simulation of silver or chrome. The bronze flake inkor the aluminum flake is treated in the same type of stamping machineand is the result of the reduction of hammered, leafed metals of bronzeor aluminum.

It is to be understood that a line bronze flake or aluminum flake willflow better and will permeate the molding material when the curing inthe molding process takes place.

To the floured molding substance a bronze flaked ink or aluminum flakeof 200 mesh with a stearine consistency is added in the proportions ofabout one ounce of bronz flake or aluminum flake to two ounces of flourmolding substance. The bronze or aluminum ink is lighter in shade thanthe final brass or gold'tone required, because the molding process willoxidize the bronze or aluminum flake and thereby regulate the bronze orgold shade desired. The same process also applies to aluminum ortinflake when-used order to obtain a silver or chrome finish.

After the flour molding substance and the flakes have been mixed, thecomplete mixture is then-polished in a brush mill until the metal flakesare adhering to the flour substance and thereby adding lustre whenbrushed on the metal flakes. r

The basi substance consisting of urea resin, such as formaldehyde urearesin, or cellulose acetate is first prepared so that it can be groundto a finish to make it suitable for introduction into a speciallyconstructed stamping mill to be mashed or crushed. In this mill thesubstance is reduced to a flour-like or flake-like consistency of about200 mesh. Thereupon a binding grease such as lard is added to give thematerial body.

T.he metal flakes, whether bronze, aluminum or other metal aftercompletion of the stamping process, are placed in a'polishing mill andpolished with stearic acid, a tablespoonful of which is added toapproximately 15 pounds of metal flake. The polishing process, asstated, is accomplished by a series of brushes, operating on a centralshaft, rubbing against the corrugated surface of the walls of thecylindrical polishing mill. This process is continued for 12 or 24 hoursdepending upon the brilliancy desired on the flake of metal.

When the flaked part of the molding material has been prepared and theronze flake or aluminum flake have been prepared in like manner, the twoingredients, the flaked molding material and the bronze flake or theflaked molding material and the aluminum flake, are mixed in quantitiesof 2 ounces of flaked molding material to 1 ounce of bronze flake oraluminum flake.

The cylindrical polishing mill polishes by rubbing the bronze flake orenclosed material against the inside corrugated surface of the mill witha' series of brushes. The flakes of the plastic material and the metalflour or flake are brushed until they adhere to each other.

It is of great importance that the mixed materials during the polishingoperation do not become overheated since they tend to stick in the mill.It is, therefore, preferable not to continue this operation over 30minutes, because this time is suflicient for brushing the flaked orfloured substanc particles and the metal particles to- 3 gather. Thisprocess will add an additional lustre to the mixture. The combinedmaterial is now suitable for molding.

When quantities of this material are introduced in the proper weightsinto the steel molds, the cured product has the appearance of brasswhere bronze flake is used or of silver or chrome where aluminum flakeis used. This material can be used industrially for the fabrication ofplastic hardware, pipe fittings, or in whatever industrial field asubstitute plastic product is desired.

This molding material is then ready to be put into steel molds andmolded into objects which give a striking resemblance to brass, bronzeor gold. Or in the case of the aluminum or tin flakes, a resemblance tosilver or chrome.

The time for curing should be limited since over exposure causes addedoxidation resulting in a dark appearance void of lustre.

It is to be understood that the invention as here described is notlimited to the details herein but that the same may be varied widelywithout departing from the spirit of theinvention as defined by thesubjoined claims.

Having described the claimed as new is: r l

1. The process for manufacturing a batch of molding material having alustrous metallic appearance to simulate metal when molded, whichprocess consists in first grinding cellulose acetate as a base, thencrushing said base to obtain a flaky or flourlike consistency and addinglard as binding material to give body to said base, crushing a metallicelement into flake-like consistency as that of said base, thenmetallizing said flaky base material by intimately mixing with saidflaky base the flaky metallic element to be simulated in the proportionsof approximately two parts of the former to one partof the latter, tocause adherence of the metallic flake to the base flake to flow betterand permeate the base material when cured in the heat molding process tosimulate the solid metal of the metallic element.

2. The process for manufacturing a batch of molding material having alustrous metallic appearance, to simulate metal when molded, whichprocess consists in first grinding cellulose acetate as a base, thencrushing said base to obtain a flaky or flourlike consistency of about200 mesh and adding lard as binding material to give body to said base,crushing a leafed metallic element into flake-like consistency as thatof said base, then metallizing said base body by intimately mixingtherewith the flaky metallic element to be simulated in the proportionsstated until the metallic flakes adhere to the base flakes and polishingthe same and to cause the metallic invention, 7 what 1 is 3. The processfor manufacturing a batch of molding material to simulate metal whenmolded,

which process consists in first grinding cellulose acetate as a base,then crushing said base to obtain a flaky or flourlike consistency ofabout 200 mesh and adding lard as binding material to give body to saidbase, crushing a hammered leafed metallic element into the same flakyconsistency as said base, then metallizing said base body by intimatelymixing therewith the flaky metallic element to be simulated after havinbeen crushed into flake-like consistency of about the same mesh as thebase, and then polishing the mixture in a brush polishing mill withstearic acid in the approximate proportions of a table spoonful ofstearic acid to 15 pounds of metallic flake and 30 pounds of base Whilepreventing overheating, until the metallic flake adheres to the baseflake and to cause the metallic flak to flow better and permeate themolding material when cured in the molding process.

4. The process for manufacturing a batch of molding material to simulatemetal when molded, which process consists in first grinding celluloseacetate in the natural shade'as a base, then crushing said base toobtain a flaky or flourlike consistency of about 200 mesh and addinglard as binding material to give body to said base, crushing a hammeredleafed metallic element into the same flaky consistency as said base,then metallizing said base body by intimately mixing therewith the flakymetal to be simulated in suitable proportions after having been crushedand reduced from hammered leaf form into flake like consistency of aboutthe same mesh as the base, and then polishing the mixture in a brushmill within a time duration of 30 minutes, with stearic acid in theapproximate proportions of a tablespoonfulof stearic acid to 15 poundsof metallic flake and 30 pounds of base to cause adherence of the flakematerials to each other with added lustre, and to cause the metal flaketo flow into and permeate the material when heat molded.

5. A molding batch simulating metal when molded, comprising an intimatemixture of cellulose acetate as a base in flake-like floured form andmetal to be simulated in similar form polished and with the flakeadhering to each other with added lustre, with lard as a binder, inproportions of about 30 pounds of base and 15 pounds of metal and themixture, together with a tablespoonful as polishing material of polishedstearic acid.

THOMAS J. HILLERY.

